The Technoids
This is an alien race created around my scratch-built tanks made from computer chips. I have envisioned them as an advanced race who have created a technology where they can take their brains and encase them in a life support system (or biopod), and there, isolated from many of the parasites and diseases, they have achieved a longevity unobtainable in their natural bodies.
Technology has become the eyes, ears, and even hands of the Technoids. Problems such as population control, unemployment, hunger, have been reduced to almost non-existent. The Technoids have been freed to focus on the higher issues of self-fulfillment. This has found an outlet in interstellar exploration and a need to find new resources to build more exploration teams. Unfortunately this often leads to violent confrontations between Technoid resource-gathering teams and the inhabitants of other systems. Given the combination of the long life a Technoid has in their biopod and the ease with which young Technoids can be grown from the genetic banks, Technoid elders have little concern for "juveniles." In fact it is not until a juvenile has reached a certain age and made some sort of achievement, either through exploration, conquest, or discovery, that they are allowed to return to one of the home worlds and be accepted back into the elder's society.
The Technoids serve as a good "enemy". The juveniles that form a task force are eager to prove themselves in combat so they can be accepted back into society. These task forces are likely to drop in on any world that looks like it might be suitable for extracting resources to be sent back to the home worlds.